Pneumatic engine or tool.



J. D. MACDONALD.

PNBUMATIG ENGINE 0R TOOL.

APPLIOATIoN FILED MAINZ. 1911. n

UNITED sraains JOSEPH D. MACDONALD, OF BTTE, MONTANA.

PNEUMTIC ENGINE OR TOOL.

Specification of Letters Patent. Application inea March aa,

Patented Nov., 5, 1912. 1911. serial No. 616,199. v

Yo all whom it may concern:

Be it known that I, J oenria D. MACDONALD, a citizen ot' .the United' States, residing at Butte, in the county of Silver Bow and State of Montana, have invented certain new and' hereinafter set forth, refercncebeing had to' theannexed drawings, wherein:

Figure l is a longitudinal sectional View,

showing the parts in that position n which.

the live air is in the act of forcing the hammer forwardly or to the lett to deliver a blow, the course of the air being shown by the arrows in full lines; llfig. 2 a similar view, the hammer being shown actually delivering a blow or coming into Contact with the drill-head or tool,the course of the exhaust air being shown by arrows in dotted lines; Fig. 3 a longitudinal sectional View of the cuter cylindricalshell or casing; Fig. 4 a longitudinal sectional view of the hammer proper; F ig. 5 a transverse sectional view, taken on the line 5--5 ot' F ig. liand Fig. C a sectional elevation upon an enlarged 'scale of the combined guide and iabutments against which the compressed air works, with the head to which the feed bar is attached, said members likewise forming the conduit through which the con'ipressed air or other motive fluid is introduced.

rlhe main object of the present invention is to producea simple and highly et'icient pneumatic too-l which by reason of its construction is small in diameter and is free of valves except the movable piston hammer itself performs the function of a valve, or apliirality of valves.

The toc-l or hammer is of the tandem type,`

and the compressed air is introduced centrally into the piston-hammer support and thence distributed through suitable ports so that it may act equally upon all of the abutments or fixed faces to cause a forward im- Dulf-:e or movement to be imparted to the hammer or movable piston. The ports are likewise arranged that immediately the hainnier has delivered its blowthe air which caused the hammer to function will be freely exhausted and the incoming compressed air will act to return the piston-hammer to its initial positionVH The force .by which the hammer is returned to its initial position preparatory to delivering a second blow is less than that which is employed in delivering the blow, and this by reason of the fact that the air actsl upon a less number of faces cr abutments inthe return stroke than it docs in the Ioutward or hammer stroke. In the present instance three abutments or faces are exposed to the compressed air in making'the outward stroke, while but two laces are brcught into use in making the re turn stroke. .lt is concen 'able that a greater cr less number oi faces may be used, but in each instance the iixed abutments or faces employed iii producing or effecting the hammer blow should lic greater in number than those employed in causing the return of the hammer to a positivi] where the live air is again delivered to the parts to etlect the hammer blow.

The accompanying drawings illustrate but one forni ot.' the invention, though it will be readily appreciated by those skilled in the art that any1 number of stages may be cmployed to produce the result above set forth.

ln the drawings l denotes a cylindrical shell or casing in the outer end of which is inserted a stem or neck 2, of a drill head 3, a cross pin l passing through an elongated slot in the reduced end 5 and serving to hold the drill in` position with reference to the casing. rlhe drill-head, as will be seen upon reference to'Figs. l and 2, is provided with channels (3 and 7 which permit the exhaust air from the hammer to pass outwardly from the tool into the hole or opening being drilled. The cylindrical shell or casing is provided with an annular internal collar or enlargement 8. near its outer end, while at the inner or right-hand end thereof the Shell is provided with an internal enlargement 9 of considerable length. Guiding ribs l0 are formed upon the inner-face of the cylinder between the collar and the enlarged port ion in which the drill proper is mounted, and a second series of ribs 11 is likewise provided between the collar 8 and the enlarged portion 9, being located somewhatl closer to said latter member than the former.:

This construction provides two enlarged chambers within the cylindrical casing l. a

long chamber formed between the collar 8` and the enlarged portion 9, and it somewhat shorter chamber between the collar 8 and the drill proper, 'which is mounted i` the Outer @ad of the shell or casing.

right-hand The inner end of the shell or casing, as will be seen upon reference .to Fig. 3, is pro vided with a series of notches 12 and in its side wall with openings 13 and 14e. A head 15 is mounted and secured in the inner or end of the cylindrical shell or casing, said head being somewhat enlarged at the outer portion thereof and provided with lugs 1o which. when the reduced por- 'tion of the head is forced into the end ofthe A hollow feed bar 18 is screwed or otherwise secured on the head and is provided with lateral ports or openings 19, which correspond with similar ports 20 formedin the head. rl`he outer face of the headis provided with circumferential grooves or channels in which are seated packing rings 21 formed of suitable material, as for instance, leather, and as will be readily appreciated the compressed air which is forced in through the feed bar-will pass into the openingsI 19 and 2O and come against the inner face of the packing rings and force the same outwardly into contact with the adjacent inner walLof the member 9, thus preventing leakage around the head.

Mounted within the cylindrical shell or casing and having its support or point of attachment in the enlarged portion 9, is a combined piston-guide and fixed abutment member, said member comprising a head 22 which makes a close fit with the bore of the enlarged portion 9, said head'carrying a spring-pressed pin 23 which, when the part-s are properly positioned, comes into alinement with the hole or opening 13 and passes outwardly into such opening, locking the head and guide against movement. Said head is likewise provided with a series of laterally-extending ports or channels 24: which terminate beneathl a packing ring 25 seated in a groove or channel formed around the outer face of the head 22. The compressed air which passes into said channels 24 forces the packing outwardly and forms a tight joint between the head 22 and the adjacent wall or face of the cylindrical shell or casing, or more specifically, the inner face of the enlarged section 9 of said shell. Extending from the head 22 is a hollow stem 26 terminating in a cylindrical head or abutment 27, and from said headthere eX- tends a second hollow stem 28 which terminates in a fixed head or abutment 29.

Leashes formed with separate sleeves threaded .or sweated onto the other portions of the structure. This construction enables the parts to be assembled, or in other words, permits the piston-hammer, hereinafter set forth, to be mounted upon the parts just described.

A continuous conduit or passage 30 ex tends through the head 22, stem 2G, head or abutment 27, and stem 28, the head 29 being solid. The stem 2(3 is provided with a port 31 adjacent to the right-hand face of the tixed abutment 2T, and the stem 28 is provided with a port 82 adjacent to the righthand end of the fixed head or abutment 29, said ports 31 and opening directly into the passage or conduit 30. The heads 27 and'29, in addition to forming fixed abutments against which the compressed air may operate, as will be hereinafter set forth, form the main guides and supports for the piston-hammer. Said piston-hammer is shown in detail in Fig. Ll. It comprises a cylindrical member 38, having at the lcft-hand or outer end thereof a closed head 34, the outer edge of which is preferably beveled or chamfered. The piston is formed with two bores or chambers, 35 and 36, the former being of a diameter slightly' less than the latter, or equal to the outer diameter of the fixed head or abutment 29, while the latter (36) is of a diameter equal to the outer diameter of the tixed head or abutment 27. The two horesl or chambers -35 and 3G are separated from each other h v .a fixed ring or collar 37 which, as will be seen, is secured in position by a. pin 3S securely driven to place, The internal. diameter of the ring or collar 37 is such as to make a close iitwith the smaller stem 2S of the hammer-piston supportover which it lslides as the piston-hammer is moved back and forth.

In the right-hand or inner end of the piston-hammerthere is secured a sleeve or bushing 39, said sleeve being held in position by a pin 40, the internal diameter of such sleeve being the same as the outer diameter of the stem 26 of the piston-guide with which it makes a relatively close lit. The piston-hammer is provided with four ports, two of which (41 and At2) open 'into the chamber 35, while the other two (43 and l) open into the enlarged chamber 36. The port 41 is located adjacent to the outer end of the chamber 35, while the port 42 is located substantially at the mid-length of said chamber Port 43 is situated adjacent to the collar or abutment 37, while the port 44 is at the mid-length of the chamber 36. Y

Aswill be seen upon reference to F l and 2, the piston-hammer makes a close fit at all times with the inner face of the ringj shaped abutment or enlargement 8, so that r Said heads 27 and 29 will preferably be l no air, or at least no appreciable amount of air, can pass between the faces of the contacting members at this point. The same is true of the head or abutment 27 and the head or abutment 29, and the faces of the chambers and`36 with which they work. Again, the stems 26 and 28 make close contact with the sleeve 39 and the collar 37 respectively, and no appreciable amount of air can pass between the contacting faces of these parts.

In operation, and having reference more particularly to Figs. l and Q, and with the understanding that the live air which is constantlyfed to the machine through the hollow feed bar is indicated by `the full-line arrows, and that the exhaust air is indicated by the dotted arrows, it will be seen that the live air passes into the conduit 30, thence outwardly.through the port 3l, into the chamber 36, thence outwardly through the port 44 into the chamber or space left between the outer tace oi the piston-hammer and the interior face of the cylindrical shell or casing, or in other words into the enlargedchamber formed in said casing, the compressed air likewise passing through the port 32 into the chamber 35, and out through the port 42 into the chamber just referred to. The air from the enlarged Chaim ber through the port 43, into the left-hand end oi the chamber 36, between the fixed abutment or head 27 and the right-hand face of the collar 3'?. The air at the same time passes between the face of the sleeve 39 and the adjacent face of the fixed head 2Q. .it also passes through the port 4l and entors thel outer end 'of the chamber 35, be tween the outer face of the fixed head or abutment 29 and the end wall 45 of the chamber lt will thus be seen that the compressed air is acting upon the pistonhammer at three diiierent points to torce the same outwardly to eti'ect a blow upon the drill-head. The compressed air continues to act to force the piston hammer outwardly until the parte reach the positionshown in Fig. 2 when, as' will be noted, the pistonhammer will have delivered its blow and the position of the ports will be so changed as to permit the air which has been acting to force the piston-hammer outwardly to be exhausted, as indicated in dotted lines in said figure. The course of the exhaust air is from the enlarged chamber into thecylindrical shell or casing, through the port 42, into the chamber 35, through the port 4l, thence through the smaller cylindrical chamber into the channels or ports 6 and 7. The air will alsoI pass through the ports 43 and 44, into the cylindrical chamber' and outwardly in the course just outlined. At the same time, the live air which is constantly fed through the feed bar and into the conduit or passage`30, will passA through the port 31 and likewise from the chamber 3GA through the port and acting upon the inner end or face of the sleeve 39 and the righbhand end of the lixed abutment 27 and against the outer tace or' the collar 37, and the inner or right-hand end or face of the abutment 29, acts to force the pistoirham- Ymer inwardly or to the right. This movement will continue until the parte assume the positions shown in Fig. l, when, as will be seen, the exhaust will have been out oli' and the live air will again act to force the piston-hamn'ier outwardly. Thev same cycle of operations will then be repeated.

From the foregoing it will be seen that the compressed air is introduced intov one end of the shell and exhausted at the opposite end. preferably through the drillhead, and that there is in eliect no reversal of the air-currents, which is a matter of importance in a tool of this character, in that it enables the drill to act with greater rapidity than where the air-currents have to be reversed, as in those drills which employ a controlling valve which acts both as an inlet and an outlet valve.

The term air in the foregoing specification and the following claims is to be understood as the equivalent oit' any suitable. gaseous medium' capable o'f being compressed and giving' oil power due to expansion. So, too, the term pneumatic i is used in its generic sense.

The introduction of air through the central conduit o1l passage 30 and the distribution of the same in the manner set forth into the piston chambers, or the chambers wi-thin the cylindrical shell or casing' surrounding the piston-hammer, enables me to produce a hammer without valves, and also to. provide a hammer of relatively small diameter, and

vone which can be carried down into the opening or hole being drilled by a mere eX- tension ot the t'eed bar. This latter feature is of marked advantage in that it brings the hammer and operating' parts thereof into close relationship with the drill-head.

lVhile the device has been described as being used in conjunction with a drill, it will be readily appreciated that it may be e1nployed for other purposes, any suitable tool being substituted for the drill herein shown.

Having thusI described I claim is:

1. ln a pneumatic hammer. the combina tion of a shell or casing adapted to carry a cutting tool at. its outer or forward end: a hollow hammer piston mounted and movable therein; and a coml'iined piston-support and abutment member located within the piston and secured to the shell, said piston and support being provided with suitable .ports for the passage of air in rear of the piston, thence forwardly7 through and in advance ollhe piston, and finally through the forward or outer' end of the casing, whereby my invention, what adapted to act in conjunction with one pair with the second of abutments, and the other pair, each of said chambers being'provided with two ports for the admission and exhaust of compressed air.

' 3. In a pneumatic hammer, the combination of a shell or casing provided with an interior enlar ement intermediate its ends; a hollow mem er secured to one end of the shell, said member being provided with a plurality of fixed heads or abut-ments, said abutments being spaced away from the wall of the shell; and a hollow hammer-piston -having one closed end and an internal abutment or enlarged member located between said end and the opposite end, said piston being mounted and movable upon the heads or abutments of the ixed member, said fixed member being provided with two 'ports which open, respectively, into the hollow piston uponopposite sides of the internal enlargement carried thereby, and said piston being likewise provided with two ports upon each side of said enlargement, said ports opening into the space intermediate` the piston and the inner wall of the shell.

4. ln a pneumatic hammer, the combination of a shell or caslng; a combined piston support and abutment member mounted `there1n,said member being hollow and having a port opening adjacent to the abutment; and a piston-han'uner mounted on said support and working in conjunction with said abutment, said piston having ports all adapted to act in conjunction with the abutment. alternately as inlet and exhaust ports,"t,he live and exhaust pressure fluid in the same general direction through the hammer in both expansive and exhaust conditions.

.5. In a pneumatic hammer, the combination -of a shell or casing; a hollow reciprocating piston mounted therein; fixed abutments Working in conjunction with the piston; and meansv for introducing the pressure-fluid. lnteriorly into the piston to cause i the same to deliver a blow and then to exhaust forwardly through the piston and shell in the same direction of movement as it had when acting to cause the blow.

6. In a pneumatic hammer, the combination of a shell or casing 'provided with an enlargement of. the .shell creasing;

internal enlargement; a hollow member se- 4cured to one end of the shell or casing and extending forwardly therein toward said enlargement; a plurality of fixed abutments carried by said member; a piston-hammer mounted and movable upon said almtments7 the outer diameter of said hammer being such as to make a close tit with the internal and a ring-shaped member mounted within Athe piston hammer and adapted to work between the outermost abutments of the fixed member aforesaid, said fixed member heilig provided with a port adjacent to each of the abutments carried thereby, and the piston-hammer being likewise provided with two pairs of ports opening into the same, one pair being located to one side of the fixed ring-shaped member and the other upon the opposite side thereof.

T. In a pneumatic.hammer, the combinaticn of a shell or casing provided with an internal enlargement vadjacent. to one end thereofga vhead fixed to the inner end of said shell or casing; a hollow feed bar connected to said head; a lixed member mounted within the shell or casing` said member being,- provided with a head adapted to be secured within the shell or casing. adjacent. to the head aforesaidand with two hollow stems extending outwardly from the head, said stems being of varying diameters, and the outer stem being smaller than the one nextA to the head; a fixed abutment carried by the stems adjacent to their point. of junc tion; avsecond abutment carried at the outer endv of the smaller stem, said stems being hollow and affording means of communication for the air from thc hollow feed bar, and each stem being provided with a port adjacent to the inner face of its abutment; a hollow piston-hammer; a lixed member secured within said piston-hammer and dividing the same into two chambers, thehores of which are. respectively, equal to the outer diameter of the fixed abutments aforesaid, said abutments working within said chambers when the parts art` assembled, and kach chamber being provided with a port located adjacent to its outer end` and with a second port extending through thc wall of the piston-hammer at approximately the mid-length thereof; a` fixed sleeve secured to one end of the piston-hammer and adapted to work over the larger stem of the fixed member; and a drill-head mounted in the outer end of the shell or casing.

8. ln a pneumatic hammer, the combination of a shell or casing provided adjacenty to one end thereof with an internal enlarge ment; a piston mounted within said shell or casing and adapted to make aclose tit with said enlargement and to be moved therethrough` said piston beinm hollow; a fixed head or abutment carriedy the shell or casing adjacent to that end opposite the internal enlargement aforesaid; a fixed abutment mounted within the hollow piston and over` which the latter is adpated to be moved back and fortlr; and a hollow member extending from the Xed head and forming the support for said fixed abut.- ment, said member being provided with a, port adjacent to the head and opening into the space left within the piston between the hollow member and the internal wall of said piston, said piston being likewise pro- 'vided with two ports, one opening into the outer end thereof and the other into the same at approximately its mid-length, whereby compressed air or other pressu-re Huid may be` introduced through the hollow member which supports the xed abutment and caused to pass outwardly through the port in said member, thence outwardly through the middle port in the piston, and

be given to the piston, the parts being so arranged that when the piston reaenes its limit of outwardI travel the air will be eX- of' the piston and the innerv'face of the fixed abutment' to cause a retrograde movement of the piston.

Y3o hausted from the parts just mentionedand l ythe live air will act upon the inner end In testimony whereof I have signed my name to this specification in the presence of two subs'cribin witnesses.

JOSE H D.' MACDONALD. lVitnesses HERBERT CRATER, FRANK E. S. MUNGER. 

